chore: add release drafter automation

[wesk]

This PR adds the following two workflows:

1. Release Drafter
   1. Automatically drafts our next GitHub release notes with each push to main
   2. Automatically proposes a new version number as a minor or patch release
   3. Based on the implementation in feat: add release drafter aws-powertools/powertools-lambda-python#56
2. Third-party workflow version pin validator
   1. Automatically validates that all third-party workflows run with a pinned version hash
   2. Based on the implementation in chore(ci): lockdown 3rd party workflows to pin sha aws-powertools/powertools-lambda-python#1301

Manual steps still required for each release:

1. Confirm that each PR title accurately captures the scope of the change. Make sure PRs are labeled as feat: or fix: etc. correctly
2. Add labels to each PR corresponding to the type of PR that it is. Release drafter functions based on the label.
3. Re-run the Release Drafter workflow after updating labels to ensure the release draft picks up the changes.
4. Fill in the "What's New" section of the GitHub release before releasing
5. Manually update the CHANGELOG file before each release
6. Verify that the inferred release version that Release Drafter proposes is correct

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[codecov]

Codecov Report

Patch coverage has no change and project coverage change: +0.33 🎉

Comparison is base (e603687) 64.76% compared to head (f8da144) 65.09%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #568      +/-   ##
==========================================
+ Coverage   64.76%   65.09%   +0.33%     
==========================================
  Files         341      363      +22     
  Lines       25538    26532     +994     
==========================================
+ Hits        16539    17271     +732     
- Misses       8999     9261     +262     

see 108 files with indirect coverage changes

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[mseeger]

I suggest to give this a try, by doing another release quite soon. Can be a patch release again.

[wesk]

Will do, thanks!

[wesk]

I suggest to give this a try, by doing another release quite soon. Can be a patch release again.

PR for a new release: #620